1. Field of the Invention
The present invention relates to locking compositions, kits containing the locking compositions and methods for maintaining the patency of a vascular access device or intravascular delivery device that employs the locking compositions. The locking composition in accordance with the present invention comprises a carrier such as water, an anticoagulant and a viscosity agent. The locking compositions useful in the present invention are free of heparin. The compositions useful in the present invention may also be hypertonic and exhibit a density and viscosity greater than the blood of the subject with the vascular access device or intravascular delivery device.
2. Description of the Related Art
Indwelling vascular catheters represent an important and common procedure performed in daily medical practice. Intravascular catheters are routinely flushed with an anticoagulant solution to prevent clotted blood from clogging the catheter lumen. In cases where catheters are left in place for long term use, flushing constitutes an important, but labor intensive, aspect of catheter care. In current medical practice, a solution of heparin in saline (e.g., sodium chloride in solution) is commonly used for this purpose, although saline alone is also used.
Although effective in preventing clotting within catheters, a significant disadvantage of such saline or heparin solutions is that they must be administered frequently, e.g., the catheter must be flushed every 4-8 hours to prevent blockage. This frequency of administration represents a considerable labor effort for healthcare providers. Furthermore, because heparin is extracted from animal tissues, it poses a potential risk of zoonotic disease transmission, as well as other quality and performance problems.
It is estimated that more than 250 million peripheral and central catheters are used each year in clinical medicine. Considering a conservative treatment regiment, a cumulative total of 900 million saline heparin flushes are administered each year. Peripheral and central indwelling catheters are used to provide an access site to the patient (subject) to administer intermittent medications, I.V. fluids or to draw blood samples. In order to maintain patency (free of blood clots) of the catheter tip a solution of heparin (10 to 100 IU)/saline or saline alone are used to fill the catheter when it is not being used. However, as many as 15% of all intermittent sites established continue to be lost due to coagulation buildup and eventual lumen blockage. An example catheter lock solution for solving these problems includes a combination of ingredients that will provide improved protection of the catheter to clot formation while being cost effective.
U.S. Pat. No. 4,929,242 describes a method and solution for maintaining the patency of a catheter during intermittent drug therapy administration. The disclosed solution consists of a carrier such as water and a density/osmolality adjusting material such as glycerol, dextrose and/or sodium chloride. The disclosed solution is adjusted to have a density and osmolality similar to whole blood.
U.S. Pat. No. 6,685,694 discloses methods and kits for locking and/or disinfecting subcutaneously and transcutaneously implanted catheters. The disclosed methods and kits require the addition of a lower alcohol to the catheter lumen in an effort to prevent fouling and plugging of the lumen.
Although the methods and compositions described in U.S. Pat. Nos. 4,929,242 and 6,685,694 are reported to improve fouling and plugging of catheter lumens, there is still a need for improvement. Accordingly, a continuing and unmet need exists for new and improved locking compositions for vascular access devices or intravascular delivery devices.
It is an object of the present invention to provide a composition for maintaining the patency of a vascular access device or intravascular delivery device that does not employ heparin.
It is a further object of the present invention to provide a composition for maintaining the patency of a vascular access device or intravascular delivery device that prevents fouling and/or plugging of the vascular access device or intravascular delivery device for more than 8 hours, preferably more than 12 hours and most preferably more than 16 hours.
It is another object of the present invention to provide a composition for maintaining the patency of a vascular access device or intravascular delivery device that exhibits a density greater than the density of whole blood and that is hypertonic.
It is also an objective of the present invention to provide a composition for maintaining the patency of a vascular access device or intravascular delivery device that exhibits antimicrobial properties.
It is also a further objective of the present invention to provide a composition for maintaining the patency of a vascular access device or intravascular delivery device that is stable upon storage for at least six months, preferably at least a year or longer, prior to use in a subject.
It is still an additional objective of the present invention to provide a composition for maintaining the patency of a vascular access device or intravascular delivery device that may be terminally sterilized after its preparation and prior to use in a subject.